Introduction: what does metabolism mean?biotech dictionary?
1.Metabolic
Pathways
one step: substrate/enzyme/product
thousands of steps in an integrated network
starting molecule (say cholesterol) step..step..step..end product (say estrogen)
enzymes as
catalysts:
enzymes are proteins!!
substrate molecule fits the enzyme’s active site like a “lock and key”
enzymes
catalyze
the chemical reaction
each enzyme is specific to a particular substrate (like a lock is only opened with a specific key)
enzymes can
add an atom,
remove an atom or
rearrange the atoms
enzymes make and/or break covalent bonds
A short metabolic pathway is illustrated in Figure 9.9 of your text.
What is the starting chemical? _______________.
What is the end product chemical? _________.
How many steps in the pathway? ________.
What is the name of the enzyme that catalyzes Step 1? ____________.
For every step in the pathway a unique enzyme is required.
Enzyme names always end in the same three letters; what are they? _____.
How many enzymes are required to accomplish the glycolysis pathway? _.
catabolic pathways
anabolic pathways
metabolism is about transforming energy from one form into another, e.g. plant photosynthesis, or a marathon runner
other examples
of energy transformation
FPL Power plant
your car
2.Energy:define energy, define matter
energy flows through the ecosystem; enters as sunlight, flows up the food chain, leaves the planet as heat
matter is recycled
Forms of energy:
kinetic
(heat)
electromagnetic
energy animation,electromagnetic
spectrum
e=mc2Implications?
energy transformations: nuclear (sun), etc.
3.Energy
transformations are subject to two Laws
Laws of Thermodynamics
1. First Law
2. Second Law
Determine which collection of atoms and molecules in the table below is more organized or ordered?
Place an "X" behind the most ordered form of matter (atoms and molecules).
matter (CO2 and H2O) in the atmosphere / or........matter(C-H-O) in a tree's tissue………
matter in the water / matter in a fish
matter in a live fish / matter in a dead fish
matter in the soi / matter in a tomato plant
a stack of toy block / blocks scattered on the floor
a well maintained house / one abandoned for 300 yrs.
gasoline in the cars tank / gas in the cars exhaust
Is order more associated with living or non living systems? _______________.
What happens to order if you do not maintain it; what will happen to a stack of cards?________
What will happen to a house over 500 years, if it is not maintained?______________________.
Which is most likely:
a pile of cards on the floor spontaneously assembles into a ordered "house of cards," or
a "house of cards" spontaneously disassembles into a pile of cards on the floor?
Is the natural tendency of nonliving matter (e.g. a pile of rocks) to become ordered or disordered?______________________.
Do healthy living chemical reactions (cells) increase order or decrease order, when compared to dead or nonliving chemical reactions? ____________.
Entropy define
How is entropy analogous to your income tax?
The magic of Life has
a thermodynamic basis:
Most chemical reactions reach an equilibrium and stop or reverse in a “dynamic equilibrium”
Video clip: calcium carbonate and calcium oxide and carbon dioxide http://www.youtube.com/watch?v=LMIbJ-B92Ho
Living chemical reactions maintain a Metabolic Disequilibrium= The Secret to the emergent property of “Life.”
questions on metabolic pathways
4.Free Energy
“Free Energy” define:
Determine which of the following energy transformations are spontaneous, i.e. can occur without the input of energy from outside the system.
Transformation Spontaneous? Encircle the spontaneous action.
water moving downhill / water moving uphill
house falling down / house being built
CO2 & H2O forming glucose / glucose breaking apart into CO2 & H2O
human growth and development / human death and decay
Endergonic and Exergonic chemical reactions: encircle "exergonic" reactions below
photosynthesis
digestion
building muscle mass
contracting a muscle to run
“burning” food to power muscle contraction
dieting
anabolic reactions
catabolic reactions
5.ATP: Coupling
exergonic reactions with endergonic with ATP
ATP is called “energy currency” molecule
Florida Power and Light converts all fuels, gas, oil, coal or nuclear, into electricity
Our cells convert all food energy, carbohydrates, lipids, or proteins, into ATP
What monomer does ATP very
closely resemble?answer
ATP = Adenosine triphosphate
ATP-ADP cycleGive some examples of“cellular work.”
Fig. 9.9 Glycolysis, Step 1, Draw hexokinase “phosphorylating” glucose
Does hexokinase use hydrolysis or dehydration synthesis to break the phosphate off ATP?
ATP powers cellular work, “by the direct chemical transfer of a phosphate functional group.”
Practice Quiz Questions on ATP
6. Enzymes catalyze chemical reactions by lowering
the “energy barrier”
burn some glucose
7.Enzymes
are substrate specific
8.Enzyme Activity: temperature, pH, cofactors, inhibitors (competitive, noncompetitive, allosteric), poisons,
9.Metabolic Order: How do cells bring order out of the chaos of chemical reactions?
turn pathways on and off:“enzyme pathway regulation” by feedback regulation,
mixing pathways and chemicals
at just the right time:cellular structure
and organelles, e.g. mitochondria
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